US3582203A - Optical zoom and image-rotating system - Google Patents

Optical zoom and image-rotating system Download PDF

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Publication number
US3582203A
US3582203A US750612A US3582203DA US3582203A US 3582203 A US3582203 A US 3582203A US 750612 A US750612 A US 750612A US 3582203D A US3582203D A US 3582203DA US 3582203 A US3582203 A US 3582203A
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Prior art keywords
image
lens
condenser
zoom lens
prism
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Expired - Lifetime
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US750612A
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English (en)
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Arthur Cox
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Bell and Howell Co
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Bell and Howell Co
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Publication of US3582203A publication Critical patent/US3582203A/en
Assigned to BELL & HOWELL COMPANY A DE CORP. reassignment BELL & HOWELL COMPANY A DE CORP. MERGER (SEE DOCUMENT FOR DETAILS). , EFFECTIVE MAY 6, 1977, DELAWARE Assignors: BELL & HOWELL COMPANY, AN ILL CORP. (MERGED INTO), DELAWARE BELL & HOWELL COMPANY, A DE CORP. (CHANGED TO)
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    • G—PHYSICS
    • G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
    • G03B—APPARATUS OR ARRANGEMENTS FOR TAKING PHOTOGRAPHS OR FOR PROJECTING OR VIEWING THEM; APPARATUS OR ARRANGEMENTS EMPLOYING ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ACCESSORIES THEREFOR
    • G03B21/00—Projectors or projection-type viewers; Accessories therefor
    • G03B21/10—Projectors with built-in or built-on screen
    • G03B21/11—Projectors with built-in or built-on screen for microfilm reading

Definitions

  • the principal object of the invention is to provide an improved cabinet-projector-type microfilm reader having prism means for projecting the image of each frame in an upright position even though two frames on the microfilm are differently oriented, and having zoom lens means for varying the magnification attwill through a 1.3-to-l range or more.
  • FIG. 1 is a schematic or block diagram of an optical system according to the invention.
  • FIG. 2 is a diagrammatic cross section of a zoom lens according to the invention.
  • FIG. 3 is a diagrammatic cross section of a prime lens according to the invention, particularly designed with its aperture stop in front of the lens for use with a zoom projector.
  • FIG. 4 is a diagrammatic cross section of a combined'image rotator and angle spreader according to the invention, which is useful with any projector within its limits of aperture and field angle.
  • FIG. 4A is an elevational view of the image rotator shown in FIG. 4, as viewed from the right end thereof.
  • FIG. 5 is a diagrammatic cross section of a zoom condenser system according to the invention and of the sealed reflector lamp with which it was particularly designed to be used.
  • FIGS. 6 and 7 show a mechanism for varying the condenser for maintaining optimum illumination.
  • FIGS. 8 to 11 show an adjustable mount for the angle spreader lenses and the prism enclosed therebetween.
  • FIG. 12 shows another form of zoom lens with which the angle spreader is adapted to be used.
  • a further object of the invention is to provide an improved zoom lens, as shown in FIG. 2, characterized in part by having its aperture stop outside the zoom lens toward the long conjugate end of the system whereby the brightness of the projected image remains constant, provided the incident light fills the aperture.
  • a further object of the invention is to provide an improved prime lens as shown in FIG. 3, having general utility in projectors requiring the aperture stop to be at a distance in front of the body of the lens, and which is particularly useful in combination with the zoom lens of FIG. 2.
  • a further object of the invention is to provide a combined angle spreader or wide-angle attachment and image-rotating prism, as shown in FIG. 4, whereby image rotation can be accomplished throughout a wider angular field than the intrinsic angular limits of the prism.
  • An object of a particular feature of the invention is to provide an image rotation prism having the aperture stop for the system near the optical center of the prism.
  • An object of a further feature of the invention is to provide a rotatable mount for the angle spreader and prism, as shown in FIGS. 8, 9, l and 11 which is inexpensive to manufacture and easy to adjust for proper alignment of the prism and lens elements with each other and with the axis of rotation.
  • FIG. 1 is a block diagram of an illumination and optical system for a microfilm reader or the like, according to the invention.
  • An incandescent lamp l0 and condenser 11 (see FIG.
  • a projection lens or prime'lens 13 forms either a real or a virtual image of the microfilm.
  • a zoom lens 14 forms an image which may be varied in size at the option of the user.
  • the zoom control is of known construction having a helical groove and a specially shaped slot, both formed in a rotatable lens tube.
  • a combined angle spreader and image rotator 15 forwardly of the zoom lens is a combined angle spreader and image rotator 15 (see FIGS. 4 and 4A) which receives light rays from the zoom lens and projects an enlarged image which may be rotated by the user so that the printed matter is right side up.
  • the rays projected from the angle spreader are reflected in three plane mirrors l6, l7 and 18 which fold the optical path for compactness.
  • the image is finally formed on a projection screen 19 for viewing from the front.
  • Mirror 18 is mounted on a hinge and may be pivoted to position 18' thereby allowing the image to be formed on a platen 20 normally supplied with photosensitive paper for making a photocopy reproduction of the printed matter.
  • the optical system has been designed to correct for spherical aberration, coma, astigmatism, distortion, lateral color, and combined variations of these aberrations, over the whole of the projection screen for all positions of the zoom control.
  • the combination of angle spreader and pechan prism is par ticularly favorable to the establishment of such an aberrational correction.
  • Each known prism type has its characteristic limiting angle of field, and outside this angle no useful light (or too little light) passes through.
  • the dove prism may have a wider limiting angle of field but must be used with substantially collimated light.
  • the present invention combines the wider field angle with the additional advantages derived from the entry and exit faces of the prism being perpendicular to the optical axis.
  • FIG. 2 shows a zoom lens according to the invention adapted to operate with an aperture stop 21 forwardly thereof.
  • a stop is provided either adjacent to or within the image rotator. (FIG. 4).
  • the zoom lens consists of a front stationary member L, to L,, a zooming member L to L of negative power and a compensation member L, to L all mounted in known manner for moving the zooming member in one direction for changing the magnification and moving the compensation member first one direction and then in the other direction for maintaining the image position.
  • the ,radii of curvature R to R the thicknesses t to t of the lens elements, the spacing between certain lens elements s, to 5, the refractive indices n for the D line of the spectrum and the Abbe dispersion numbers V are as listed in table I.
  • the and signs indicate curvature convex and concave to the front, respectively. Dimensions are in inches but of course may be scaled to a larger or smaller size.
  • FIGS. 8, 9, 10 and 11 are views of the novel mount for the image rotator and angle spreader.
  • a pullylike ring 81 is FIG. 3 shows the prime lens and table II gives the lens data in the same manner as table I.
  • FIG. 4 shows the combined an le s reader and ima e rotaoi' in axial section and FIG. 4A shows the prisms P and P in elevation.
  • the image rotating prism and its principle of operation are well known and are fully described in various well- "I known optics books.
  • An odd number of reflections are m required (five in this case) and the axial ray emerges along the identical straight line along which it entered.
  • Two reflections take place by total internal reflection at a pair of closely spaced internal surfaces which are traversed by the beam between these two reflections. It is believed to be be novel to insert a thin sheet of opaque material between these surfaces as indicated by a section line in FIG. 4.
  • the sheet of opaque material is provided with an opening (normally round) which functions as the aperture stop of the system. It should be noted that an aperture stop in this position (about midway between the two members) is favorable for uniform illumination of the projected image while retaining a prism of compact physical size.
  • the sheet of opaque material may be eliminated and the internal diagonal surfaces aluminized except for an aperture stop formed by a circularly shaped, nonaluminized, clear area through which the reflected rays may pass without restriction.
  • the angle spreader includes fine lens elements I. to 1. and is especially designed for correction of the image aberrations in conjunction with the prism between the two members. Constructional data for this lens is given in table III in the same manner as above.
  • the bearing is made in at least two pieces for inserting the pulley.
  • the body 82 of the prism mount may be formed integral with the pulley and consists of two rings 83 and 84 rigidly connected by a horizontal bar 85.
  • the bar 85 is flat on the face toward the axis of rotation for receiving a lower plate 86 ofa prism clamp assembly, which in turn is held to an upper plate 87 by screws 88 for clamping the prism.
  • the prism unit is held against bar 85 by a tongue and pin 89 inserted in the front ring 84. This pin has sufficient play for rotatably adjusting the prism about pin 90 by engaging a hole in bar 85 until it is finally firmly held by screws 91.
  • a front lens mount 93 is held against thefront ring 84 by three screws 95 which pass through oversized holes in the lens mount. Before these screws are tightened, the mount is adjusted by rotation about pin 94 engaging a hole (not shown) in ring 84 so that the axis of the lenses L to L is adjustable in a substantially vertical direction along the central portion of a circular are 96.
  • the rear lens mount 103 is mounted against the rear ring 83 for adjustment of its axis in a horizontal direction along are 106 by slight rotation around pin 104 in exactly the same manner before screws 105 are finally tightened.
  • Insert lens 1-5 of FIG. 4 adjust the front and rear cells about pins 94 and 104 so that all coma is removed from one collimator image and tighten screws 95 and 105.
  • Screws 91, 95 and 105 may be fixed with cement to prevent later disassembly by the customer who may not be equipped to realign the parts.
  • FIG. 5 is an optical diagram of the condenser system including a ISO-watt projection lamp 10 with sealed-in reflector. Mirrors M and M allow the condenser system to be folded into a small cabinet. One member, consisting of two lenses L and L is movable for maintaining optimum illumination during zooming. The mechanism for moving these lenses is described below with reference to FIGS. 6 and 7.
  • An optical system for a cabinet-type microfilm projector comprising the following parts operatively aligned on an optical axis: (1) a light source and mirror unit; (2), a condenser; (3) a film gate through which the condenser is adapted to 5 and 7 Show the mechanism for moving the direct light from the lamp; (4) a prime lens for projecting an denser lens elements L L under the control of the zoom lens image f fil l d i h fil t (5) a o m len h vi g a 14.
  • the sleeve 61 of the zoom lens is turned for zooming in the bl Zooming member f varying he ma ifi ti n manner know" mechanical compensation y through a range of at least 1.33 to l at the option of the user;
  • This SIeCVC iS provided a toothed ring engages a a combined angle preader and image rotation unit con- Pinion mmmted with a friction P y 64 on an auxiliary sisting of a positive lens component adjacent the zoom lens, a A flexible cable 66 is wrapped around the P y 64 a negative lens component spaced therefrom and a pechan-type sufficiemynumbel' of times (about 3) P pp g and 40 inverting prism therebetween having two closely spaced interis p under tension y coil p g This cable Passes nal faces through which the light beam passes, the whole unit over an idler pulley 70 and is attached to a sliding carriage 71 being mounted f i-otation around
  • cioseiy spaced fa e of h pechan prism and by a lens 12 shows another Zoom lens and Prime lens syslem ponent of the condenser being movable under the control of With which the angle spreader and image rotator iS adapted to the movement of the ooming member of the oom lens be used.

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  • Physics & Mathematics (AREA)
  • General Physics & Mathematics (AREA)
  • Lenses (AREA)
  • Projection Apparatus (AREA)
US750612A 1968-08-06 1968-08-06 Optical zoom and image-rotating system Expired - Lifetime US3582203A (en)

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US75061268A 1968-08-06 1968-08-06

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US (1) US3582203A (fr)
CH (1) CH506804A (fr)
DE (1) DE1939629A1 (fr)
FR (1) FR2015169A1 (fr)

Cited By (12)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3848520A (en) * 1972-07-24 1974-11-19 Gerber Scientific Instr Co Line drawing photoexposure device with image rotating means
US3981574A (en) * 1973-12-17 1976-09-21 Addressograph Multigraph Corporation Optical device
US4531831A (en) * 1981-11-11 1985-07-30 Canon Kabushiki Kaisha Variable magnification image formation apparatus
US4733951A (en) * 1987-04-01 1988-03-29 Minnesota Mining And Manufacturing Company Zoom lens having magnification factors in the range of 6.5x to 14x for micrographic applications
US4743102A (en) * 1987-04-01 1988-05-10 Minnesota Mining And Manufacturing Company Zoom lens having magnification factors in the range of 12X to 24X for micrographic applications
US4746204A (en) * 1987-04-01 1988-05-24 Minnesota Mining And Manufacturing Company Zoom lens having magnification factors in the range of 14X to 32X for micrographic applications
US4750820A (en) * 1987-04-01 1988-06-14 Minnesota Mining And Manufacturing Company Zoom lens having magnification factors in the range of 20X to 47X for micrographic applications
US4981351A (en) * 1985-02-14 1991-01-01 Canon Kabushiki Kaishi Film retrieving apparatus
US5062695A (en) * 1989-02-28 1991-11-05 Minolta Camera Kabushiki Kaisha Zoom lens system for use in a microfilm projection apparatus
US6688525B1 (en) 1999-09-22 2004-02-10 Eastman Kodak Company Apparatus and method for reading a coded pattern
US9977224B2 (en) 2016-08-22 2018-05-22 Largan Precision Co., Ltd. Optical imaging system, imaging apparatus and electronic device
US12321038B2 (en) 2015-07-24 2025-06-03 Largan Precision Co., Ltd. Optical photographing lens assembly, image capturing device and electronic device

Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2434378A (en) * 1944-07-15 1948-01-13 Sun Chemical Corp Photographic reversing unit and system for producing reversed images
US2815696A (en) * 1953-10-27 1957-12-10 Viewlex Inc Brightness control means
US3286592A (en) * 1961-04-22 1966-11-22 Wagner Helmut Objective with continually variable focal length and fixed image plane
US3354776A (en) * 1964-11-20 1967-11-28 Bell & Howell Co Microfilm reader
US3497289A (en) * 1967-09-25 1970-02-24 Bausch & Lomb Prism variable anamorphic optical system

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2434378A (en) * 1944-07-15 1948-01-13 Sun Chemical Corp Photographic reversing unit and system for producing reversed images
US2815696A (en) * 1953-10-27 1957-12-10 Viewlex Inc Brightness control means
US3286592A (en) * 1961-04-22 1966-11-22 Wagner Helmut Objective with continually variable focal length and fixed image plane
US3354776A (en) * 1964-11-20 1967-11-28 Bell & Howell Co Microfilm reader
US3497289A (en) * 1967-09-25 1970-02-24 Bausch & Lomb Prism variable anamorphic optical system

Cited By (15)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3848520A (en) * 1972-07-24 1974-11-19 Gerber Scientific Instr Co Line drawing photoexposure device with image rotating means
US3981574A (en) * 1973-12-17 1976-09-21 Addressograph Multigraph Corporation Optical device
US4080056A (en) * 1973-12-17 1978-03-21 Addressograph Multigraph Corporation Optical device
US4531831A (en) * 1981-11-11 1985-07-30 Canon Kabushiki Kaisha Variable magnification image formation apparatus
US4981351A (en) * 1985-02-14 1991-01-01 Canon Kabushiki Kaishi Film retrieving apparatus
US4746204A (en) * 1987-04-01 1988-05-24 Minnesota Mining And Manufacturing Company Zoom lens having magnification factors in the range of 14X to 32X for micrographic applications
US4743102A (en) * 1987-04-01 1988-05-10 Minnesota Mining And Manufacturing Company Zoom lens having magnification factors in the range of 12X to 24X for micrographic applications
US4750820A (en) * 1987-04-01 1988-06-14 Minnesota Mining And Manufacturing Company Zoom lens having magnification factors in the range of 20X to 47X for micrographic applications
US4733951A (en) * 1987-04-01 1988-03-29 Minnesota Mining And Manufacturing Company Zoom lens having magnification factors in the range of 6.5x to 14x for micrographic applications
US5062695A (en) * 1989-02-28 1991-11-05 Minolta Camera Kabushiki Kaisha Zoom lens system for use in a microfilm projection apparatus
US6688525B1 (en) 1999-09-22 2004-02-10 Eastman Kodak Company Apparatus and method for reading a coded pattern
US12321038B2 (en) 2015-07-24 2025-06-03 Largan Precision Co., Ltd. Optical photographing lens assembly, image capturing device and electronic device
US9977224B2 (en) 2016-08-22 2018-05-22 Largan Precision Co., Ltd. Optical imaging system, imaging apparatus and electronic device
US11789244B2 (en) 2016-08-22 2023-10-17 Largan Precision Co., Ltd. Optical imaging system, imaging apparatus and electronic device
US12386153B2 (en) 2016-08-22 2025-08-12 Largan Precision Co., Ltd. Optical imaging system, imaging apparatus and electronic device

Also Published As

Publication number Publication date
DE1939629A1 (de) 1970-03-05
FR2015169A1 (fr) 1970-04-24
CH506804A (fr) 1971-04-30

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AS Assignment

Owner name: BELL & HOWELL COMPANY A DE CORP.

Free format text: MERGER;ASSIGNORS:BELL & HOWELL COMPANY, AN ILL CORP. (MERGED INTO);DELAWARE BELL & HOWELL COMPANY, A DE CORP. (CHANGED TO);REEL/FRAME:004195/0168

Effective date: 19830907